ANTIFRICTION ELEMENT FOR USE BETWEEN RELATIVELY SLIDING COMPONENTS OF AN ADJUSTABLE STEERING COLUMN

Abstract: An antifriction element (1) for use between two relatively sliding metal components (2, 3) of an adjustable steering column is locatable between the two components and is formed such that, in an unclamped state of the components, two opposed resilient flanges (7) act to urge the components away from contact with one another to allow relative free sliding of the components on the element (which is of plastics material) and, in a clamped state of the components, the flanges are deflected to allow direct contact between surfaces of the metal components to provide the clamping friction.

Description: ANTIFRICTION ELEMENT FOR USE BETWEEN RELATIVELY SLIDING COMPONENTS OF AN ADJUSTABLE STEERING COLUMN This invention relates to an antifriction element for use between relatively sliding components of an adjustable steering column construction for a vehicle. With known constructions of clamping mechanisms for adjustable steering columns, whether rake and/or reach adjustable, the clamping mechanism allows relative sliding between one part of the steering column and another part of it in an undamped condition, whilst the two parts are clamped together once the desired location has been set by the driver. The two parts are metal and so the relatively sliding metal faces can give an unsatisfactory "feel" to the user. According to one aspect of the present invention, there is provided an antifriction element for use between relatively sliding components in a clamping mechanism of an adjustable steering column construction for a vehicle, the element being locatable between two said components, characterised in that, in an undamped state of the components, a part of the element acts to urge the components away from contact with one another to allow relative free sliding of the components on the element and, in a clamped state of the components, said part is deflected to allow direct contact between surfaces of the components to provide the clamping friction. The invention also extends to an adjustable steering column incorporating an antifriction element essentially as just defined. According to another aspect of the present invention, there is provided a steering column clamping mechanism for an adjustable steering column comprising: a first clamp member; a second clamp member slidable relative to the first clamp member, the first clamp member and the second clamp member being in contact with one another when the steering column is in a clamped state; and an antifriction element interposed between the first clamp member and the second clamp member, characterised in that the antifriction element biasses the first clamp member and the second clamp member out of contact with one another when the steering column is in an undamped state, the first clamp member and the second clamp member each being in sliding contact with the antifriction element when the steering column is in the undamped state. Preferably, the antifriction element is formed of a plastics material, the relatively sliding components being of metal. The element can be in the form of a flanged, slotted liner, the or each flange of the liner having a degree of resilience and being formed in such a way as to constitute said part as hereinbefore defined. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 is a diagrammatic perspective view of an antifriction element for use between relatively sliding components of an adjustable steering column construction for a vehicle. Figure 2 illustrates the antifriction element of Figure 1 located between two such relatively sliding components in an undamped condition, Figure 3 is a view similar to Figure 2 but showing the clamped condition. Figure 4 is a side view, partly in section, which shows an adjustable steering column construction incorporating two such antifriction elements, one being for a linear adjustment of the steering column and the other being for a vertical adjustment of the steering column, and Figure 5 is an end view in section of the construction illustrated in Figure 4. Referring to Figure l, the antifriction element illustrated is in the form of a slotted, flanged plastics liner 1 for interposition between two relatively sliding components 2, 3, respectively, of an adjustable steering column for a vehicle. The liner 1 has a substantially rectangular form with a longitudinal slot 4 to accommodate an adjustment bar 5 of the adjustment mechanism, the adjustment bar 5 being linked to a clamp handle 6 (Figures 4, 5) of the clamping mechanism. As shown in Figure 4, two liners 1 are provided, one of them (1A) being for linear or reach adjustment of the steering column and the other (IB) being for vertical or rake adjustment of the column. As best seen in Figure 1, the liner 1 has two opposing flanges 7 extending in its free state at an angle from the plane of an upper surface 8 of the liner. As illustrated in Figures 2 to 5, the plastics liners 1 are located between the two relatively sliding metal components 2, 3 and Figure 2 shows that, when the clamping mechanism is in its undamped condition, the flanges 7 of the liner 1 act to urge the components 2 and 3 away from one another so that relative sliding takes place on the plastics surface 8 of the liner 1 in a low friction manner (rather than the greater frictional reaction as would be the case of relatively sliding metal components in direct contact with one another) . Figure 3 illustrates the components in the clamped condition of the mechanism and here it will be seen that the flanges 7 have been deflected towards the plane of the surface 8 by the components 2 and 3 being pressed one against the other, so that the adjacent surfaces of the components 2 and 3 contact one another to provide a high resistance clamp force in a metal-to-metal contact. As previously stated, Figure 4 shows two such liners although it will be appreciated that only one such liner need be provided for a mechanism which only adjusts in one plane. The part labelled 2/3 in Figure 5 is of course the metal component 3 which is clamped into contact with the metal component 2 of the vertical adjustment liner IB and it is also the metal component 2 which comes into contact with the metal component 3 with the interposition of the liner 1A of the linear adjustment facility. Thus, the present construction of the element allows for a duel purpose slotted liner which allows low friction plastics contact for adjustment and high friction metal contact for positive locking of the mechanism.

Claims: CLAIMS : 1. An antifriction element (1) for use between relatively sliding components (2, 3) in a clamping mechanism of an adjustable steering column construction for a vehicle, the element (1) being locatable between two said components (2, 3), characterised in that, in an undamped state of the components, a part (7) of the element acts to urge the components away from contact with one another to allow relative free sliding of the components on the element and, in a clamped state of the components, said part is deflected to allow direct contact between surfaces of the components to provide the clamping friction. 2. An element according to claim 1, and being made of plastics material. 3. An element according to claim l or 2, and being in the form of a flanged, slotted liner (1), the or each flange (7) of the liner having a degree of resilience and being formed in such a way as to constitute said part. 4. An element according to claim 3, wherein two said flanges (7) are provided, one on each opposing side of a surface (8) of the liner on which one of said components (2, 3) is intended to slide, the flanges extending in the free state of the liner at an angle to said surface of said liner. 5. An element according to claim 4, wherein the slot (4) of said liner is in said surface (8) of said liner. 6. An adjustable steering column for a vehicle, incorporating an antifriction element according to any one of the preceding claims. 7. An adjustable steering column according to claim 6, wherein two said elements (l) are provided, one for use in connection with rake adjustment and the other for use in connection with reach adjustment. 8. A steering column clamping mechanism for an adjustable steering column comprising: a first clamp member (2); a second clamp member (3) slidable relative to the first clamp member, the first clamp member and the second clamp member being in contact with one another when the steering column is in a clamped state; and an antifriction element (1) interposed between the first clamp member and the second clamp member, characterised in that the antifriction element (1) biasses the first clamp member (2) and the second clamp member (3) out of contact with one another when the steering column is in an undamped state, the first clamp member and the second clamp member each being in sliding contact with the antifriction element when the steering column is in the undamped state.

Inventors: BARTON LAURENCE GEORGE HERBERT, BARTON, LAURENCE, GEORGE, HERBERT
Applicants: TORRINGTON CO, THE TORRINGTON COMPANY LIMITED
Application year: 1994
Main classification: B62D1
IPC codes: B62D1, F16B5, F16C29